Outline

Garlic (Allium sativum) and leek (Allium porrum) are two members of the Alliaceae family and are commonly used as food and herbal supplements with diverse health benefit effects including an antiviral activity. Garlic bulbs accumulate several sulfur-containing compounds (including alliin and allylsulfides) and two types of mannose-binding lectins [Allium sativum agglutinin I (ASA-I) and ASA-II]. The in vitro antiviral activity of a standardised garlic extract on SARS coronavirus strain Frankfurt 1 (SARS-CoV FFM1) was evaluated by a colorimetric cell proliferation assay. A dose dependent inhibitory effect was evident when garlic extract was added to Vero E6 cells infected with 100 CCID50 of SARS-CoV. The antiviral effect of garlic was further examined by testing the SARS-CoV inhibitory activity of alliin, allylsulfide, allyldisulfide, allylmethylsulfide and the garlic lectins ASA-I and ASA-II. No activity could be demonstrated neither for the lectins nor for the sulfur-containing compounds. However, the in vitro anti-SARS-CoV activity of the Allium porrum agglutinin (APA), an oligomannoside-specific lectin encoded by leek, was also investigated. APA was found to inhibit SARS-CoV replication by 50% at a concentration below 1 Âµg/ml. No measurable cytotoxicity could be demonstrated at 54 Âµg/ml resulting in a remarkable selectivity index greater then 150 in this cell model. Although the effective garlic compound has not yet been identified, we demonstrate in this study that members of the Alliaceae family show interesting anti-SARS-CoV properties, which in case of leek are produced by the leek lectin.